Linear actuators are used to transform rotation of a motor into linear motion of rod operating mechanisms such as gears, screw shafts, nuts, etc. For that purpose, a ball screw mechanism is commonly used.
Linear actuators usually require electrical switching in order to be operative. Unlike conventional mechanisms utilizing cables, links and the like, which encounter problems such as troublesome mounting and inoperativeness due to freezing or rust, linear actuators are especially preferred for manipulating devices such as valves, clutches, and engine throttles. However, since actuator positioning is performed by mechanical force, an operator is unable to "feel" whether or not the actual positioning took place. Therefore, it is necessary to provide some means for confirming that the operation has occurred. Many of the devices in the prior art are unreliable and provide false verifications.